Records and distribution of the coral-killing sponge Chalinula nematifera in the Ryukyu Islands, Japan

We report the presence of the coral-killing sponge species Chalinula nematifera (de Laubenfels, 1954) in southern Japan via photographic records and specimens. The species appears to be a substrate generalist on scleractinians and occasionally octocorals, and is found across a wide variety of depths (0 to 24 m), as has been recently reported for this species from Indonesia. From our information, the species is found in southern Japan across the southern and central Ryukyu Islands, with a northern limit of Amami-Oshima Island, although future work will likely expand the range. As our records stretch back more than 20 years, we do not believe Chalinula nematifera is a recent arrival to the region. Due to the potential for this species to harm coral reefs, we suggest field surveys are needed to establish a baseline distribution and abundance database to aid in future monitoring.